Method for forming structured polymeric film

Abstract

A method for forming a structured polymeric film having a plurality of longitudinally spaced structured on both sides of the structured polymeric film is described. The method includes: providing a rotatable tool having an outer circumferential surface, the outer circumferential surface including a plurality of tool projections; providing a nip roll having a smooth conformable outer circumferential surface opposed to the outer circumferential surface of the tool; introducing a polymer layer into a nip between the tool and the nip roll; pressing the polymer layer between the tool and the nip roll to form web recesses into a first side of the polymer layer and web projections extending away from an opposing second side of the polymer layer, with the tool projections on the circumferential surface of the tool and form a structured web; and removing the structured web from the tool. Sample processing articles are also described.

1. A method for forming a structured polymeric film having a plurality of longitudinally spaced structures on both sides of the structured polymeric film, comprising:
 providing a rotatable tool having an outer circumferential surface, the outer circumferential surface including a plurality of tool projections; 
 providing a nip roll having a smooth conformable outer circumferential surface opposed to the outer circumferential surface of the tool, the nip roll having a conformable outer circumferential surface of a Shore A hardness in the range of 30 to 100; 
 introducing a transparent polymer layer and an opaque polymer layer into a nip between the tool and the nip roll; 
 pressing the polymer layers between the tool and the nip roll to form web recesses into a first side of the opaque polymer layer and web projections extending away from an opposing second side of the transparent polymer layer, with the tool projections on the circumferential surface of the tool and forming a structured web, the tool projections having a height greater than the total thickness of both polymer layers; and 
 removing the structured web from the tool; 
 
       said transparent polymer layer being further from the tool projections in the nip than the opaque polymer layer, whereby the resulting structured web has recesses having opaque side walls and transparent bottom surfaces. 
     
     
       2. A method according to  claim 1  wherein the providing a nip roll step comprises providing a nip roll having a conformable outer circumferential surface of a Shore A hardness in a range from 40 to 90. 
     
     
       3. A method according to  claim 1  wherein the providing a nip roll step comprises providing a nip roll having a conformable outer circumferential surface of a Shore A hardness in a range from 50 to 85. 
     
     
       4. A method according to  claim 1  wherein the introducing step comprises introducing a molten polymer layer into a nip between the tool and the nip roll. 
     
     
       5. A method according to  claim 1  wherein the introducing step comprises introducing a molten first polymer layer and molten second polymer layer into a nip between the tool and the nip roll. 
     
     
       6. A method according to  claim 1  wherein the introducing step comprises coextruding a first polymer layer and second polymer layer into a nip between the tool and the nip roll. 
     
     
       7. A method according to  claim 1  wherein the structured web is divided into a plurality of sample processing articles.